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Stephen Perrenod’s research area was clusters of galaxies and their X-ray emission. He holds Ph.D. and Master’s degrees in Astronomy from Harvard University and a Bachelor’s in Physics from MIT.
He created the first computer model for the evolution of X-ray clusters of galaxies over cosmological time scales.
After his career in astrophysics he moved into the high performance computing field, where he has worked for over a quarter century. He has been a frequent public speaker on HPC, Grid and Cloud computing topics.
When he was active in astrophysics in the 1970s, the cosmological constant – which now is of such great significance – was usually dismissed as unlikely to have a non-zero value.
His latest book is 72 Beautiful Galaxies, designed for the iPad, and focused on the lovely images of galaxies with short explanations. Suitable for ages 10 to 99.
He currently consults to technology companies in the areas of AI, Big Data and High Performance Computing (www.orionx.net)
https://www.goodreads.com/book/show/19448565-dark-matter-dark-energy-dark-gravity
Dark Matter, Dark Energy, Dark Gravity 
February 2nd, 2013 at 1:07 pm
Hello Stephen!
I just found your web site and it looks great. I’m very interested in dark matter (and also the hypothesized first quantum particle of the universe) and have some new ideas about it. I have a B.Sc. from MIT also (’67), an M.Sc. physics from University of Illinois and a Ph.D. in Psychology (’77) (experimental) from Stanford. My website is http://www.superluminalquantum.org and I have a new article there called “A tranluminal energy quantum model of the cosmic quantum” . A spinoff from this model is two possible candidates for dark matter particles — a fermion and a boson. I’m planning to present this work at the coming APS April meeting in Denver. I would very much like to discuss some of these ideas with you and hear your ideas also if you’re interested. The article mentioned above will be published in a scientific proceedings book by World Scientific this summer.
all the best,
Richard Gauthier
richgauthier@gmail.com
Santa Rosa, CA
January 18th, 2017 at 8:26 pm
You posted an error at Quora, fyi, I couldn’t see how to comment there so am letting you know here:
10^36 / 10^26 = 10^10, not 10^7 as you said:
2 Answers
Stephen Perrenod
Stephen Perrenod, physics degree from MIT and astrophysics Ph.D. from Harvard
Written Dec 15, 2015
Paul’s answer is a good start, but most stars are less massive than the Sun. Searching I found an estimate for the Milky Way’s luminosity to be 5 x 10^36 watts, whereas the Sun’s luminosity is about 4 x 10^26 watts, so the answer is roughly 1.3 x 10^7 of whatever the Sun’s mass conversion rate is.
That being about 4.3 million tons per second as Paul gave.
So the galaxy’s mass consumption is about 50 x 10^7 or 500 million metric tons per second.
May 5th, 2018 at 4:00 am
so linking mass to time (metric tons per second) doesn’t give any further clue? help me disambiguate the formulation ” galaxy’s mass consumption is about 50 x 10^7 or 500 million metric tons per second.”
we’re time and space multiplied by probability 😉